Re: vacation message & schema design

[Leif Johansson <leifj@it.su.se>]

> That would give us 11 or so object classes, one for each optional
> feature in the mail system, just so we could use LDAP to store mail
> information.  Most mail objects would need at least 5-6 object classes.
> *Not* good.  I haven't seen many schemas that follow that philosophy
> either.

Not only is it good schema design it is based on good OO design
principles: Use interfaces (which is exactly what an aux object class
is) and in the case of LDAP polymorphism to expose specific features
to applications.

I don't believe you can show me a deployed schema which actually relies
on empty IA5Strings. In fact as I have noted elsewhere in this thread
most client libraries could not distinguish empty strings from an absent
attribute-value.

> If a user wants to add a vacation message which requires that he also
> adds an object class, he must have write access to add that object
> class.  He might not have write access to modify all of his own entry.

Value-based ACL:s are supportet in many implementations. Give the user
right to add the specific object class value.

In any case I believe that your example fails to clearly show that 0-
length IAString values are ok where 0-length DirectoryStrings are not.

I.e if I were to accept your example as an argument I could construct
another example based on an attribute which required the DirectoryString
syntax (some form of a name for instance) but which, because of the
size-restrictions on DirectoryString, would not be a valid schema.

To convince me you need to construct an example which does not make
sense when the syntax is a DirectoryString! I dare you to come up with
that :-)

	MVH leifj